Process of making insulating material



, full, clear, and exact description,whereby any UNITED STATES PATENTOFFICE.

JOHN GRAY AND CHARLES H. CASE, OF SOUTH MANCHESTER, CONNECTICUT.

- PROCESS OF-NlAKING INSULATING MATERIAL.

SPECIFICATION forming part of Letters Patent No. 589,256, dated August31, 1897.

Application filed May 16, 1896. Serial No. 591,852. (No specimens.)

To all whom it may concern.- v

Be it known that we, JOHN GRAY and CHARLES H. CASE, citizens of theUnited States, and residents of South Manchester, in the county ofHartford and State of Connecticut, have invented certain new and usefulImprovements in Processes of Makinglnsulating Material, of which thefollowing is a one skilled in the art can make and'use the same.

The object of our invention is to provide an improved process forforming a material composed mainly of paper-stock or like fibrousmaterial and that shall render it firm, hard, waterproof to a degree,and particularly usable as an insulating material, although capable ofuse for many other purposes in the arts.

To this end the invention consists in the process of treatingpaper-stock or like fibrous pulp in a bath of melted sulfur, andsubsequently setting it by immersing in a cold liquid, and it alsoconsists in details of the process resulting in various forms of theproduct, as hereinafter described, and more particularly pointed out'inthe claims.

In carrying out the invention we take a quantity of paper-stock or stuffmixed-and beaten up in any well-known manner of preparing the stockwhether it be of linen, hemp, flax, wood, or other fiber. The form inwhich thisstock is first prepared, whether in sheet or in block, dependsupon the use to which the material is to be subsequently put, but itwill be largely prepared in the form of sheets of greater or lessthickness, the stock preferably containing an oxid of iron or othermetal. A quantity of this stock after being formed to shape is plungedinto a bath of melted sulphur at a temperature of about three hundredand ten degrees (310) Fahrenheit and retained in the bath long enoughfor the. sulfur to thoroughly permeate and unite with the material. Itis then subject to pressure, as between rolls or in a press, and if itis desired to prevent the material from warp ing is plunged into a bathof cold liquid, as water, after being pressed. It is preferred that therolls or molds by means of which pressure is applied shall be heated toa degree to prevent chilling the material before it is formed. Theimproved material thus made can be filed, sawed, cut with the ordinarywoodworking and some iron-Working tools, and turned to shape, care beingonly required that the speed of the lathe in turning shall be about thespeed required for turning metal, or but little more. This material isparticularly useful for insulating purposes, and .when prepared insheets can be cut to the desired shape and form in strips for washers orfor any other desired purpose.

The pulp 'can be molded to the desired shape for cut-out boxes,switch-bases, and for other purposes, then subjected to the sulfurtreatment, to pressure, and then turned down to the required shape.

The material thus made is capable of a high degree of polish, as it isfirm, non-fibrous, and capable of being cut to any desired shape withtools, as described.

After the mass of material has been treated in the melted sulfur andsubsequently subjected to heat and pressure, as between rolls, asurface-scale is formed which is a detriment to the commercial useof thearticle unless such scale shall be removed. This may be done, as bymeans of any suitable cutting or grinding device. After this film hasbeen removed the surface of the material can be brought to a high degreeof polish by suitable tools.

lVe claim as our invention 1. The improved process of making aninsulating material consisting in forming a mass of pulp to shape,heating the same in a bath of molten sulfur, and subsequently settingsuch articlebyiinmersion in a cold bath.

2. The improved process of making an insulating material consisting informing a mass of pulp to shape, heating the same in a bath of moltensulfur, then subjecting the mass to heat under pressure, andsubsequently setting such article by immersion in a cold bath.

JOHN GRAY. CHARLES H. CASE.

Witnesses:

GHAs. L. Boanurr,

J. STERN.

